<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input id="t1" type="text">
<input id="b1" type="button" value="添加">
<ul id="u1">
    <li>1</li>
    <li>2</li>
</ul>
<script src="jquery-1.12.4.js"></script>
<script>
    $('#b1').click(function () {
        var v =$('#t1').val();
        var temp = "<li>"+v+"</li>";
        $('#u1').append(temp)
    })
</script>
</body>
</html>